Product Details:

MODICON AS-BDA0-21 is a high precision single channel analog output module for the legacy AEG Modicon A120 Compact PLC platform. It receives digital commands transmitted from the main CPU over the dedicated A120 backplane bus and converts digital values into standard 4-20 mA analog current signal to drive field control valves, positioners and proportional actuators for closed-loop process regulation. This module adopts 12-bit conversion resolution and supports full-scale calibration to guarantee stable and accurate current output for flow, pressure, temperature and liquid level control loops. It provides galvanic isolation between the backplane logic side and the field analog loop to suppress ground loop interference. It plugs directly into the A120 rack slot and draws operating power from the backplane. Front panel LED indicators display module ready status and fault alarm for convenient on-site inspection and troubleshooting. Integrated EMC filtering and surge suppression circuits protect the analog output wiring from voltage spikes and electromagnetic noise generated in heavy industrial environments. As an obsolete original spare part, it is used for maintenance and retrofit of aging Modicon A120 Compact automation systems. Direct drop-in replacement keeps the existing actuator wiring, loop load configuration and PLC register mapping unchanged, removing the requirement to redesign analog control loops and cutting production downtime.

Basic Parameters

Product type: single channel analog D/A output module

Compatible platform: Modicon A120 Compact PLC

Output signal: 4-20 mA DC current

Resolution: 12 bit

Isolation: 2500 VAC isolation

Max loop load: 500 Ohm

Installation: rack slot mount for A120 dedicated backplane

Operating temperature: 0°C ~ +55°C

Protection grade: IP20

Supported Functions

Digital to analog conversion for 4-20mA output

Full scale calibration and signal scaling

Isolated analog loop driving

Module self-diagnosis and fault flag output

Backplane high-speed data exchange with host CPU

Transient overvoltage and noise suppression for field loop

Core Functions

Real-time conversion of digital setpoint to stable analog current

Continuous current drive for process regulating actuators

Onboard LED ready and fault indication

Galvanic isolation to eliminate ground loop noise

Diagnostic alarm for open loop or hardware failure

Synchronous data reception from the A120 backplane bus

Hardware Specifications & Environmental Features

Built-in analog signal filtering and surge suppression circuit

Storage temperature: -20°C ~ +65°C

Relative humidity: 5% to 90% non-condensing

Status: Obsolete original part, available for spare replacement

Industry Applications:Applied in legacy petrochemical distributed control, old paper making production automation, water treatment remote signal collection and large conveyor remote I/O control racks.

Note:Confirm A120 backplane compatibility, loop resistance and scaling parameter before ordering.

This is from our current stock.

available stock.xlsx